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Light environment in the Arctic differs widely with the seasons. Studies of relationships between objectively measured circadian phase and amplitude of light exposure and melatonin in community-dwelling Arctic residents are lacking. This investigation combines cross-sectional (n = 24-62) and longitudinal (n = 13-27) data from week-long actigraphy (with light sensor), 24-h salivary melatonin profiles, and proxies of metabolic health. Data were collected within the same week bracketing spring equinox (SE), and winter/summer solstices (WS/SS). Drastic seasonal differences in blue light exposure (BLE) corresponded to seasonal changes in the 24-h pattern of melatonin, which was phase delayed and reduced in normalized amplitude (NA) during WS/SS compared to SE. The extent of individual melatonin's acrophase and Dim Light Melatonin Onset (DLMO) change from SE to WS correlated with that from SE to SS. Although similar in extent and direction, melatonin phase changes versus SE were linked to morning BLE deficit in WS, contrasting to evening BLE excess in SS. Seasonal changes in sleep characteristics were closely associated with changes in the phases of BLE and melatonin. Proxies of metabolic health included triglycerides (TG), high-density lipoprotein cholesterol (HDL), TG/HDL ratio, and cortisol. Adverse seasonal changes in these proxies were associated with delayed acrophases of BLE and melatonin during WS and SS. TG and TG/HDL were higher in WS and SS than in SE, and cross-sectionally correlated with later melatonin and BLE acrophases, while lower HDL was associated with later BLE onset and later melatonin acrophase. Overall, this study shows that optimal 24-h patterns of light exposure during SE is associated with an earlier acrophase and a larger 24-h amplitude of melatonin, and that both features are linked to better metabolic health. Improving light hygiene, in particular correcting winter morning light deficit and summer evening light excess may help maintain metabolic health at high latitudes. Novel solutions for introducing proper circadian light hygiene such as human-centric light technologies should be investigated to address these issues in future studies., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

PreHevbrio® is a 3-antigen HBV vaccine (3-A-HBV) engineered to express the three HBV envelope proteins; the small 'S' hepatitis B surface antigen (SHBs or HBsAg), the middle pre-S2 + HBsAg (MHBs) and the large PreS1 + PreS2 + HBsAg (LHBs) antigens. 3-A-HBV has been shown to induce superior and more durable antibody responses relative to a 1-A-HBV despite containing half the 'S' antigen dose. To explain the mechanism(s) behind the high immunogenicity, the potential influence of mammalian glycosylation, HBs antigen conformation, anti-HBs epitope binding profiles and T-cell responses to the PreS antigens were investigated. In this paper, we demonstrate that glycosylation status does not play a role in the increased immunogenicity of the 3-A-HBV, but that the 3-A-HBV particles are able to induce T cell responses to PreS1 and PreS2 antigens. Epitope mapping demonstrated that the 3-A-HBV particles are inherently more antigenic than 1-A-HBV particles, leading to quantitative differences in the anti-HBs antibody response. Further, we demonstrate that the T cell responses significantly correlate with the higher observed anti-HBs titers and may contribute to the higher and more durable anti-HBs titers. This trial is registered at Clinicaltrials.gov (NCT03393754) and EudraCT (2017-001819-36)., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: David E Anderson reports financial support was provided by VBI Vaccines Inc. David E Anderson reports a relationship with VBI Vaccines Inc. that includes: employment and equity or stocks. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Illia Petrov reports statistical analysis was provided by VBI Vaccines Inc. Illia Petrov reports a relationship with VBI Vaccines Inc. that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Barthelemy Ontsouka reports financial support was provided by VBI Vaccines Inc. Barthelemy Ontsouka reports a relationship with VBI Vaccines Inc. that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Catalina Soare reports financial support was provided by VBI Vaccines Inc. Catalina Soare reports a relationship with VBI Vaccines Inc. that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Daniel Plaskin reports financial support was provided by VBI Vaccines Inc. Daniel Plaskin reports a relationship with VBI Vaccines Inc. that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Lanjian Yang reports financial support was provided by VBI Vaccines Inc. Lanjian Yang reports a relationship with VBI Vaccines Inc. that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Rachel Hammond reports a relationship with Clear B Therapeutics that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Tamara Berthoud reports financial support was provided by VBI Vaccines Inc. Tamara Berthoud reports a relationship with VBI Vaccines Inc. that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Tanvir Ahmed reports financial support was provided by VBI Vaccines Inc. Tanvir Ahmed reports a relationship with VBI Vaccines Inc. that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Francisco Diaz-Mitoma reports a relationship with VBI Vaccines, Inc. that includes: consulting services and equity stocks. If there are other authors, they declare that they have no known competing financial interest or personal relationships that could have appeared to influence the the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)